I don't see that as a fair comparison. The number of people who are rich enough to buy a particular home for more than the hypothetical actual value is orders of magnitude greater than the number of people who can afford to buy up all the lots around a home at a premium and affect its property value. As a result, the perceived threat to the homeowner is substantially different. I also think you're ignoring the psychological costs of this. It doesn't actually have to happen, just the potential that it could happen would be a real fear for many people. Moving is one of the most stressful events in people's lives, much less unplanned moving. There's also empirical data showing negative outcomes for children.